Patent document 1 discloses a technique for an active anti-vibration supporting device. In a conventional technique disclosed in patent document 1, a target lift amount for a movable member of an actuator of an active control mount is calculated based on the output signals from an engine rotation speed sensor, a load sensor and an acceleration sensor in one vibration cycle of an engine. The duty ratio of a duty group for controlling driving current output to the actuator in the next vibration cycle is determined based on the calculated target lift amount. At this time, the phase delay which is the timing of the start point of the duty group is also determined.
Further, in the next cycle, the actuator of the active anti-vibration supporting device is driven based on the first, second and third duty groups corresponding to the vibration cycle lengths T1, T2, T3. When the engine rotation speed is increased and the cycle lengths T1, T2, T3 . . . are gradually shortened, current fed to the actuator is not eliminated at the end of the first, second and third duty groups, but the peak value of the current is gradually increased to prevent the active anti-vibration supporting device from achieving effective vibration-proofing functions, while generating possibility of heat generation at the actuator. In the conventional technique disclosed in patent document 1, the duty ratio for the second duty group is set at zero to stop energization to the actuator when the overlap quantity of the first and the second duty group exceeds a threshold.